Photographically sensitive additive color screen element and process of additive color photography



Aprll 26, 1955 LAND 2,707,150

PHOTOGRAPHICALLY SENSITIVE ADDITIVE COLOR SCREEN ELEMENT AND PROCESS OF ADDITIVE COLOR PHOTOGRAPHY Filed Aug. 5, 1952 l4 Phoi'osensifive L y r Screen k RW PHM Receiving Elemeni L H 20 L1 FIG. I

Suppor'l' FIG. 2

mix/5M ATTORNEY United States Patent O PHOTOGRAPHICALLY SENSITIVE ADDITIVE COLOR SCREEN ELEMENT AND PROCESS OF ADDITIVE COLOR PHOTOGRAPHY Edwin H. Land, Cambridge, Mass., assignor to Polaroid Corporation, Cambridge, Mass., a corporation of Delaware Application August 5, 1952, Serial No. 302,744

12 Claims. (Cl. 952) This invention relates to photography and more particularly to processes and products for use in the production of color images.

In my copending application Serial No. 641,808, filed January 17, 1946, for Photographic Product Comprising an Additive Color Screen, a Silver Halide Layer and a Rupturable Container and a Process of Additive Color Photography, I have disclosed a one-step additive color photographic process and products for carrying out the same wherein an additive color screen, through which the negative or photosensitive element is exposed, is further utilized for viewing purposes and as at least a part of a sheet structure providing a print-receiving element which is adapted to carry a transfer image of positive silver.

Objects of the present invention are to provide novel procedures useful in one-step photography wherein the filter media of an additive color screen associated with a silver halide photosensitive layer and through which said layer is exposable are. dissolved in the processing reagent employed to develop a latent image and form transferable silver complex and, together with said silver complex, are transferred in solution in said reagent to a transparent, permeable stratum of image-receptive material in which a positive silver image is formed and said color screen is reproduced; as well as to provide novel products for carrying out said process, especially products comprising a photosensitive layer which carries an additive color screen formed of filter media of a character soluble at least in an aqueous alkaline liquid and arranged in a screen pattern at least over the exposure face of the photosensitive element for solution in an aqueous alkaline processing reagent permeated into the photosensitive layer whereby to permit transfer of the filter media along with silver complex dissolved in said reagent to a print-receiving stratum for reproduction of said screen and formation of a positive silver image.

These and further objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and relation and order of one or more of such steps with respect to each of the others, and the product possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description, taken in connection with the accompanying drawing, wherein:

Figure 1 is a longitudinal, diagrammatic, fragmentary, sectional view of a novel photographic product for carrying out the novel process of the invention, said product being shown with the thicknesses of the various layers or strata thereof greatly exaggerated; and

Fig. 2 is a schematic, sectional view of an embodiment of a print-receiving element usable with the photosensitive or negative element of the product of Fig. 1.

As it is now well understood by the art, a photographic transfer process may be utilized to provide in a print receiving element, having at least a permeable stratum of an image-receptive material, a reverse image of a latent image contained in a photosensitive layer of a silver halide photosensitiveelement. In carrying out a silver halide photographic transfer process, a liquid composition comprising a silver halide developer and a silver halide fixer may be substantially uniformly permeated 2,707,150 Patented Apr. 26, 1955 into the exposed silver halide layer. The liquid develops the latent image in the silver halide layer and forms a soluble silver complex, e. g., a thiosulfate or a thiocyanate with undeveloped silver halide, which is transferred in solution to a print-receiving element located in superposed relation to the photosensitive layer where this complex is developed to silver to provide the desired reverse image.

Additive color reproductions may be produced by these practices by exposing a color-sensitive silver halide layer, for example a panchromatic photosensitive layer, through an additive color screen having filter media or screen elements each of an individual additive color such as red or blue or green and by viewing the reverse or positive silver image formed by transfer in a transparent, printreceiving element through the same or a similar screen which is suitably registered with the reverse image carried by the print-receiving element.

One embodiment of a multilayered and sheetlike film assembly or unit suitable for carrying out. the invention is illustrated in Fig. l and comprises a photosensitive or negative element 10 which is arrangeable in superposed relation to a print-receiving or positive element 11. A mpturable container 15 adapted to contain a liquid processing reagent is mounted on one of the layers of the product at a position between two of the layers of the product.

Photosensitive element 10 comprises a support 12 of conventional film base material. Mounted on the support 12 is a photosensitive layer 14 comprising a commercially available panchromatic silver halide gelatin emulsion. The material of support 12 may comprise conventional support paper and may be opaque as shown or it may be a conventional transparent plastic such as cellulose ester or mixed ester, for example cellulose nitrate, cellulose acetate, cellulose acetate propionate, or other materials which will form a continuous film for use in supporting a photosensitive layer.

A carrier material for the silver halide of the photosensitive layer may comprise gelatin or other liquidpcrmeable material such as regenerated cellulose; polyhydroxy alkanes such as polyvinyl alcohol; sodium alginate; cellulose ethers, such as methyl cellulose, or their derivatives such as sodium carboxymethyl cellulose; proteins such as fish glue or albumen; as well as mixtures of such materials where they are compatible.

Print-receiving element 11 is shown in Fig. 1 as comprising a single sheet of a transparent material which may be permeable to the liquid processing composition or may, as will hereinafter more fully appear, be substantially impermeable thereto. An organic plastic material such as the polyvinyl alcohol or the regenerated cellulose named as a carrier material for the photosenitive silver halide may be employed to provide a liquidpermeable print-receiving element. When an impermeable print-receiving element is used, substantially liquid-impermeable transparent plastic sheeting such as that named in connection with the film base material may be utilized. Alternatively, the print-receiving element may utilize a structure such as that shown in Fig. 2 wherein an element 30 is disclosed as comprising a transparent support 31 of a substantially liquid-impermeable material upon which a liquid-permeable stratum of a print-receptive material 33 is carried.

Container 15 is adapted to releasably contain a suitable processing liquid which comprises at least an aqueous alkaline solution. Such a processing liquid is a solvent for a silver halide developer and a silver halide fixer, both of which may be included in the liquid. One function of the alkali is to provide an accelerator for the developer. Alternatively, the silver halide developer and/or fixer may be incorporated in some layer of the film assembly into which the processing reagent is penetrated. In a preferred embodiment, the container contents also will include an organic, film-forming agent such, for example, as carboxymethyl cellulose, which will of course increase the viscosity of the liquid reagent. As will presently appear, an added function of the alkali in the processing liquid is to assure the solution of filter media in the reagent.

The container 15 is preferably inexpensive and disposable and so constructed as to be capable of retaining the liquid processing agent or composition therein for relatively long periods of time without vapor loss or oxidation. One example of a suitable container of this type is formed from a single multilayer sheet of material comprising three laminae. The inner lamina, which provides the inner surface of the container, is formed of a material which is chemically inert to the reagents in the processing agent and which is impervious to the liquid of the agent. One class of material suitable for this purpose, particularly where the processing agent is an alkaline solution, is the polyvinyl acetals, and of the acetals, polyvinyl butyral is a preferred species. A composition comprising 60% to 72% by weight of polyvinyl butyral, 10% to 23% by weight of nitrocellulose, and approximately 5% by weight of dibutyl sebacate is satisfactory as the inner lamina. The intermediate lamina is preferably impervious to the vapor of the processing agent and is formed, for example, of a metallic foil such as lead or silver foil. The outer or backing lamina is formed of a strong, deformable, relatively inexpensive sheet material such as a kraft paper.

A container may be made from a single sheet of the just-described three-ply material by folding the same along the longitudinal axis and thereafter securing the end marginal portions and the overlying marginal portions of the two folded faces of the sheet one to the other whereby to provide a space or cavity for containing the processing liquid. The marginal portions of the overlying container walls along the long edges thereof which are removed from the fold are preferably sealed together by a bond which is weaker than the bond securing the end portions thereof. This may be effected by the control of heat and/ or pressure employed for sealing said long edges of the container in conjunction with an overcoat of ethyl cellulose or ethyl cellulose and paraffin provided as a strip on the inner surface of one of the overlying container walls along said long edge thereof. As a result, the application of pressure to the opposite sides of the container will effect the rupture of this weaker bond along said edges to permit discharge of the liquid from the container. To fill the container, it is possible to adhere together said long edges thereof and one of the end marginal portions and to then fill the container through the other end, after which the last-mentioned end is sealed.

The film assemblies of this invention may be in the form of cut film or in the form of roll film. When used as roll film, two or more containers 15 are mounted at spaced intervals on one of the layers of the assembly, for example upon the print-receiving element, as shown in Fig. 1. These intervals will be such that an individual container will be located adjacent one end of each picture frame of the film assembly. The photosensitive element 10 and the print-receiving element 11 may be connected by fastening means (not shown) comprising one or more hinges, staples or the like, whereby these elements may be spread apart and angularly inclined to each other to permit exposure of the photosensitive element from the side thereof which is superposable in overlying relation to the print-receiving element.

Further details of film assemblies, container structures and processing compositions of the character described in connection with the film unit of Fig. 1 are set forth in my Patent No. 2,543,181, issued February 27, 1951, for Photographic Product Comprising a Rupturable Container Carrying a Photographic Processing Liquid.

Additionally, the photosensitive element of the film assemblies of this invention are provided with an additive color screen formed of materials which are soluble in the liquid reagent used in processing the film assembly and particularly water-soluble dyes and dyes which are soluble in aqueous alkaline solutions. The color screen is provided by ruling or printing a regular or irregular color screen pattern on the exposure face of the photosensitive element with two or more dyes or dye solutions of appropriate color to provide two or more sets of color filter media wherein the screen components of each set are individually of the same color but of a color different from the components of another set. A two-color or three-color screen may be employed, for example a screen formed of red components, blue components and green components.

As noted, the screen components comprise dyes. Preferably, dyes are employed which exert at least a negligible desensitizing effect upon the emulsion or the photosensitive material. As will hereinafter be pointed out in more detail, the dye solutions employed may be penetrated through the photosensitive layer or only for a portion of the thickness thereof and, by the use of suitable control techniques, may be retained substantially at the exposure face of the emulsion whereby the penetration of the dye solution is negligible.

The photosensitive element 10 is illustrated with a color screen having a line pattern and comprising red components 16, green components 18 and blue components 20 which have been incorporated in the photosensitive layer 14, including the exposure face thereof, by the practices just described and which, for the purposes of illustration, have been shown as penetrated into the photosensitive layer for about one-half its thickness. As previously pointed out, this penetration is controllable and may be for the full thickness of the photosensitive layer or the penetration may be restrained to a negligible amount.

ln carrying out the novel process of the invention, the film assembly of Fig. 1 is first exposed through the exposure face of the photosensitive layer 14 so that the exposure thereof is effected through the color screen carried by the photosensitive layer 14 and made up of the screen components 16, 18 and 20. Thereafter the film assembly is subjected to pressure as by being passed between a pair of pressure-applying rolls which are adapted to press together the opposite faces of the assembly. These rolls may be located in the camera in which the film unit is exposed and, as the film assembly passes between the rolls, the containerlS is ruptured and the reagent is released and is spread between the opposed surfaces of the photosensitive element 10 and the printreceiving element 11. Reagent permeated into the photosensitive layer 14 and containing developer and fixer in solution develops the latent image therein, forms soluble silver complex with the unexposed silver halide and at least in part dissolves dyes of the filter media.

Soluble silver complex and screen dyes in solution in the reagent in the photosensitive layer are transported, at least in part, by imbibition toward the print-receiving element 11 and are deposited at least in a liquid-permeable stratum of the print-receiving element where the complex is reduced to silver to provide the desired reverse image. In carrying out this procedure, the photosensitive element and the print-receiving element are held in such close proximity to each other that the imagewise distribution of silver complex formed as a result of the development of the latent image is transferable to the print-receiving stratum substantially without being disturbed. Similarly, screen dyes in solution in the liquid reagent permeated into the photosensitive layer will be transported by imbibition to and deposited in the printreceiving stratum substantially without disturbing the screen pattern of the filter media whereby to duplicate or reproduce the color screen initially carried by the photosensitive layer.

During this transfer, the photosensitive element and the print-receiving element are held against relative movement with respect to each other in direction parallel to the planes of the layers of the film assembly. This just-noted factor permits the color screen deposited in the printreceiving stratum and the positive print formed therein to be located in register with each other and with the negative image developed in the photosensitive layer.

Following rupture of the container and the spreading of its liquid content, the layers of the film unit are retained together as a unitary structure and in the absence of actinic light for a time sufficient to permit the deposition in the print-receiving element of the silver complex and its reduction to silver and also the deposition of screen dyes therein to reproduce the color screen. This time period, commonly called the imbibition time, is for about one minute. Suitable camera constructions whereby the processing may be carried out in the absence of actinic light are now well known, and film units of this invention are particularly adapted for use with such cameras. Following the completion of processing, i. e., formation of the reverse image and reproduction of the color screen in the print-receiving stratum, the unitary structure is separated by stripping the photosensitive layer from the print-receiving layer.

In instances wherein the print-receiving element 11 is formed of a permeable sheet material and the liquid processing composition contains no film-forming agent, the positive print and the color screen will be formed in the sheet 11 which constitutes the print-receiving element. On the other hand, a film-forming agent may be added to the liquid processing composition in sufficient quantity to provide a permeable and continuous film which may be adhered to the print-receiving element 11 and in which positive image-forming components and screen dyes may, at least in part, be deposited. Thus, if the element 11 is permeable, the positive image and the reproduction of the color screen may be in part located therein and also in part in the layer of film-forming material supported thereon. In the practice of this procedure, the layer of film-forming material superposed upon the printreceiving element may be retained thereon or stripped therefrom.

When the print-receiving element 11 of Fig. 1 is of a substantially impermeable material such as any of the film base materials heretofore mentioned, it is necessary to include a film-forming agent in the liquid processing composition so as to provide, upon processing of the film assembly, a liquid-permeable stratum which will be adhered to the surface of the element 14 and in which the positive or reverse image will be formed and the color screen reproduced.

A preferred film-forming material is a high molecular weight polymer as, for example, a polymeric watersoluble ether inert to an alkaline solution as, for example, hydroxyethyl cellulose or sodium carboxymethyl cellulose. Other film-forming materials may, of course, be employed.

Formulations for the liquid processing reagent for carrying out the just-noted practices are set forth in my Patent No. 2,543,181 and in said application Serial No. 641,808.

It is likewise within the scope of this invention to employ a print-receiving element comprising a substantially liquid-impermeable support 31 formed, for example, of any of the previously mentioned film base materials and carrying upon one surface a liquid-permeable stratum 33. A print-receiving element of this character is disclosed in Fig. 2 and is adapted to be associated with the photosensitive layer 10 of Fig. 1 in place of the printreceiving element 11.

The liquid-permeable stratum 33 is preformed on the support 31 and may comprise a hardened layer of any.

of the film-forming agents heretofore mentioned, for example, sodium carboxymethyl cellulose. Preferably, however, the stratum 33 is of an extremely thin nature and comprises a macroscopically continuous matrix consisting essentially of submacroscopic agglomerates of particles of water-insoluble, inorganic, chemically inert, adsorbent substances. The word submacroscopic refers to a class of sizes which includes as a subclass those sizes known as submicroscopic. The substance preferably has a low coefficient of absorption for light as compared to silver and the matrix formed therefrom is essentially free of protective colloid action for silver. One example of such a matrix is a layer of silica such as is formed by drying a layer of an aqueous dispersion of the silica aerogel available under the trade name Santocel C.

The use of a silica matrix of the character described is desirable in conjunction with the employment of silver precipitating agents which are incorporated in the matrix. In the formation of silver prints by transfer processing, the presence of certain compounds and elements has a desirable effect on the amount and character of the silver precipitated during image formation. For this purpose, such materials as, for example, the metallic sulfides and selenides, the thiooxalates, the thioacetamides and others may be employed. Details of a silica matrix in which precipitating agents have been incorporated are set forth in my copending application Serial No. 265,413, filed January 8, 1952, for Photographic Product.

As a further concept, the invention includes the incorporation of a dye mordant in the print-receiving element. The use of a mordant provides means for controlling the precipitation in the print-receiving element of screen dyes transported thereto and assists in effecting their deposit at desired locations. The use of mordants is particularly suited for embodiments of the invention utilizing a preformed print-receiving stratum or a printreceiving element constituted by a single permeable layer as, for example, in Fig. l, and permits a mordant to be incorporated therein. If the mordant is soluble in a processing reagent which includes a film-forming material adapted to provide a print-receiving stratum, it may be included in the reagent and will be distributed in the layer provided by the film-forming agent. Conventional photographic mordants may be employed for this purpose, such as those commonly used in dye transfer papers and, for example, nickelous sulfate or aluminum sulfate.

Dyes which provide the filter media should be soluble at least in aqueous alkaline solutions and may be water soluble. Conventional and well-known dyes may be used for forming the screen although, as previously pointed out, dyes which exert a negligible desensitizing action upon the photosensitive silver halide are preferred.

Specific examples of water-soluble dyes comprise Fast Fushine G (C. I. 29), Tartrazine, and Alpha Zurine 2B (C. I. 712), which are dyes respectively possessing the subtractive colors of magenta, yellow and cyan. For providing the additive color red, aqueous solutions of the magenta dye and the yellow dye are appropriately mixed, as is well understood by the art. Green is provided by mixing cyan and yellow dye solutions, while blue is provided by a mixture of aqueous solutions of magenta and cyan.

In general, alkali-soluble but water-insoluble dyes are preferred for reasons which will become apparent. The alkali-soluble dyes are also soluble in conventional organic solvents, for example, acetone or alcohol, which are at least diflicultly penetrable into gelatin. Examples of dyes which are soluble in alkali and in organic solvents but which are insoluble in water are 1,5'dlihydroxy naphthalene-4-azo benzene for magenta; benzene azo resorcinol for yellow; and Iosol Blue for cyan, the last-mentioned dye being commercially available under that name from the National Aniline Division of the Allied Chemical and Dye Corporation. Dyes in the foregoing example have subtractive colors, and solutions thereof are intended to be mixed, in the manner described above, to provide the additive colors of red, blue and green.

As previously pointed out, the color screen is formed by printing or ruling the components thereof upon the exposure face of the photosensitive layer 14 in an irregular pattern or a regular pattern such as the line pattern disclosed in Fig. 1. Also, as has been noted, penetration into the photosensitive layer of the dye solutions adapted to provide the screen is controllable. In this regard, penetration of a dye solution into the photosensitive layer may be restricted to a negligible depth so that the dye is located substantially at the exposure face of the layer or the penetration may be such that the dye extends depthWise of the layer for the thickness of the layer or to some depth between these extremes.

In connection with penetration control, it may be noted that a predetermined quantity of dye will be required to provide a screen element of the desired optical qualities. If this dye is water soluble and is dissolved in a large volume of water, it will be more deeply penetrated into the photosenitive layer than if the volume of water is limited to provide, for example, a paste. In regard to a dye which is water insoluble but alkali soluble and which is dissolved in an organic solvent, it should be noted that organic solvents are generally difiicultly penetrable into gelatin so that a screen component applied from such a dye solution will remain substantially at the surface of the photosensitive layer 14. However, many organic solvents are water miscible, and penetration of a dye in a solution of an organic solvent may be increased by the addition of Water to the solution. Thus, the penetration of both types of dyes into the photosensitive layer is controllable within the limits set forth.

Other factors afiecting dye penetration include the molecular weight of the dye molecule itself. It will be more difficult to penetrate large dye molecules into the photosensitive layer than small ones. Additionally, the affinity or the substantivity of the dye for the carrier material of the photosensitive layer will affect the penetration of the dye solution into said layer.

In general, it is preferable to maintain the screen dyes substantially at the exposure face of the photosensitive layer 14. Such practice is preferable in that it will assist in controlling possible sidewise diffusion. of the screen dyes when they are transported towards the print-receiving element for deposit in the latter. Also, if the dyes used for the screen possess the ability to desensitize the photosensitive element, this action is restricted by reason of their limited contact with the light-sensitive silver halide distributed throughout the photosensitive layer. A subsance such as a film-forming agent, for example carboxymethyl cellulose, which is permeable to the liquid reagent used for processing the film unit and which will adhere to the surface of the photosensitive layer thereof and to which the screen dyes are substantive, may, if desired, be added to the dye solutions in instances where the screen components are to be located substantially at the surface of the photosensitive layer.

While the film assemblies have been disclosed as having a construction which requires the separation of the photosensitive element from its superposed and generally parallel relation to the print-receiving element for the purpose of exposure, it is possible to expose these film assemblies through the support for the photosensitive element. For example, if the support 12 is transparent and the dyes of the color screen are penetrated through the photosensitive layer 14 for the full thickness thereof, the photosensitive element may be exposed through the support 12. These and similar modifications are deemed to fall within the scope of the invention.

Since certain changes in carrying out the above process, and certain modifications in the product which embody the invention, may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative only and not in a limiting sense.

What is claimed is:

1. In a color photographic process making use of an additive color screen for taking and viewing purposes, the steps of forming a latent image in a color-sensitive, silver halide photosensitive layer by exposing said layer with actinic light directed through said screen and onto a face of said photosensitive layer which constitutes an exposure face thereof and with which said screen is substantially coextensive, said color screen comprising filter media which are soluble in an aqueous alkaline reagent and which are at least two different colors corresponding to the additive colors desired for said screen and said filter media being carried by said photosensitive layer in an arrangement providing a screen pattern extending over the exposure face of said photosensitive layer, developing the latent image in said photosensitive layer to silver by uniformly distributing within said photosensitive layer an aqueous alkaline reagent in which said filter media are soluble and comprising a developer and a silver halide solvent which forms a soluble silver complex with unexposed silver halide and forming a solution containing soluble silver complex and filter media in said reagent, transferring from said photosensitive layer, by imbibition, silver complex and filter media in solution in said reagent to at least a stratum of a liquid-permeable transparent layer constituting a receiving layer for said com plex and said filter media and arranged in superposed relation to said photosensitive layer on the side thereof which includes said exposure face whereby to provide in conjunction with said photosensitive layer a unitary structure, holding said layers fixed against any appreciable relative movement in a direction parallel to the planes of said layers while transporting to said stratum sufficient silver complex to form in said stratum a positive silver image of the said latent image and sufficient filter media to form in said stratum a color screen which substantially duplicates the color screen through which said photosensitive layer is adapted to be exposed, and thereafter separating said photosensitive layer from said unitary structure.

2. A color photographic process as defined in claim 1 wherein said reagent includes a film-forming material adapted to form a solid, permeable, transparent film and wherein said process includes the step of forming, in said unitary structure on the side of said photosensitive layer which includes said exposure face and with said filmforming material, a transparent film in a layer which is adapted to receive at least a part of the siliver complex and the filter media transferred from said photosensitive la er.

2). A color photographic process as defined in claim 1 wherein said photosensitive layer comprises a panchromatic silver halide emulsion and said color filter mediacomprise red components, blue components and green components.

4. A color photographic process as defined in claim 1 wherein said color filter media comprise dyes which are of different colors and which are soluble in said aqueous alkaline reagent.

5. In a color photographic process making use of an additive color screen for taking and viewing purposes, the steps of forming a negative latent image in a photosensitive element comprising a color-sensitive, silver halide photosensitive layer having at least on the exposure face thereof filter media providing a color screen, by exposing said photosensitive element through said screen, said color screen comprising filter media which are soluble in an aqueous alkaline reagent and which are of at least two different colors corresponding to the additive colors desired for said screen and which are arranged in a screen pattern to extend at least over said exposure face of said silver halide layer, developing the latent image in said photosensitive element to silver by absorbing into said silver halide layer an aqueous alkaline reagent in which said filter media are soluble and comprising a developer and a silver halide solvent which forms a soluble silver complex with unexposed silver halide and form-ing a solution containing soluble silver complex and filter media in said reagent, bringing a transparent, liquid-permeable sheet material into faceto-face contact with the exposure side of said photosensitive element, transferring from said photosensitive element, by imbibition, silver complex and filter media in solution in said reagent to said sheet material and forming therein a positive image of said negative image and also a color screen which substantially duplicates the color screen through which said photosensitive element is adapted to be exposed, and thereafter separating said sheet material from said photosensitive element.

6. As a new article of manufacture, a photographic product adapted to have formed therein a reverse image of a latent image contained in a photosensitive layer, said product comprising a negative photographic element, including at least a color-sensitive, silver halide layer providing the photosensitive layer of the product and an additive color screen comprising filter media which are soluble in an aqueous alkaline reagent and which are of at least two different colors corresponding to the additive colors desired for said screen carried by said photosensitive layer and which are arranged in a screen pattern to extend at least over one face of said photosensitive layer which constitutes an exposure face thereof whereby said photosensitive layer is exposable by actinic light transmitted through said face and said screenfa sheetlike support, said negative element and said sheetlike support being positioned in superposed relation to each other with said exposure face of the photosensitive layer located next to said support and said negative element and said sheetlike support, when so positioned being releasably held in said superposed relation, said sheetlike support providing means for supporting in integral attachment therewith, on the side thereof next to said negative element, at least a permeable stratum of an image-receptive material adapted to constitute a print-receiving layer. a rupturable container holding an aqueous alkaline liquid reagent, said container being carried by one of the layers of said product and being located between said print-receiving element and said screen for releasing its liquid content for permeation into said photosensitive layer and through said screen upon the rupture of the container and the spreading of its liquid content in contact with said exposure face of said negative element and said print-receiving element, said product containing a silver halide developer and a silver halide solvent soluble in said reagent and rendered effective to develop said latent image and to form for transfer from said photosensitive layer said reverse image in a solution containing silver complex and said filter media.

7. A new article of manufacture as defined in claim 6 wherein said reagent includes a film-forming material adapted to form a solid, permeable, transparent film adapted to receive silver complex and filter media transferred from said negative element.

8. A new article of manufacture as defined in claim 6 wherein the photosensitive layer of said negative element comprises a panchromatic silver halide emulsion and said colored filter media comprise red components, blue components and green components.

9. A new article of manufacture as defined in claim 6 wherein said filter media comprise dyes which are of different colors and which are soluble in said aqueous alkaline reagent.

10. A new article of manufacture as defined in claim 6 wherein said filter media extend inwardly from the exposure face of said photosensitive layer of said negative element at least for a part of the thickness of said photosensitive layer.

11. A new article of manufacture as defined in claim 6 wherein said sheetlike support is a transparent plastic material having a stratum ot' a liquid-permeable material supported upon one surface thereof to provide said image-receiving stratum.

12. A new article of manufacture as defined in claim 6 wherein said sheetlike support is a transparent, organic References Cited in the file of this patent UNITED STATES PATENTS 1,918,208 Larsen July 11, 1933 2,339,951 Schettler et al Jan. 25, 1944 FOREIGN PATENTS 402,599 Great Britain Dec. 7, 1933 

1. IN A COLOR PHOTOGRAPHIC PROCESS MAKING USE OF AN ADDITIVE COLOR SCREEN FOR TAKING AND VIEWING PURPOSES, THE STEPS OF FORMING A LATENT IMAGE IN A COLOR-SENSITIVE, SILVER HALIDE, PHOTOSENSITIVE LAYER BY EXPOSING SAID LAYER WITH ACTINIC LIGHT DIRECTED THROUGH SAID SCREEN AND ONTO A FACE OF SAID PHOTOSENSITIVE LAYER WHICH CONSTITUTES AN EXPOSURE FACE THEREOF AND WITH WHICH SAID SCREEN IS SUBSTANTIALLY COEXTENSIVE, SAID COLOR SCREEN COMPRISING FILTER MEDIA WHICH ARE SOLUBLE IN AN AQUEOUS ALKALINE REAGENT AND WHICH ARE AT LEAST TWO DIFFERENT COLORS CORRESPONDING TO THE ADDITIVE COLORS DESIRED FOR SAID SCREEN AND SAID FILTER MEDIA BEING CARRIED BY SAID PHOTOSENSITIVE LAYER IN AN ARRANGEMENT PROVIDING A SCREEN PATTERN EXTENDING OVER THE EXPOSURE FACE OF SAID PHOTOSENSITIVE LAYER, DEVELOPING THE LATENT IMAGE IN SAID PHOTOSENSITIVE LAYER TO SILVER BY UNIFORMLY DISTRIBUTING WITHIN SAID PHOTOSENSITIVE LAYER AN AQUEOUS ALKALINE REAGENT IN WHICH SAID FILTER MEDIA ARE SOLUBLE AND COMPRISING A DEVELOPER AND A SILVER HALIDE SOLVENT WHICH FORMS A SOLUBLE SILVER COMPLEX WITH UNEXPOSED SILVER HALIDE AND FORMING A SOLUTION CONTAINING SOLUBLE SILVER COMPLEX AND FILTER MEDIA IN SAID REAGENT, TRANSFERRING FROM SAID PHOTOSENSITIVE LAYER, BY IMBIBITION, SILVER COMPLEX AND FILTER MEDIA IN SOLUTION IN SAID REAGENT TO AT LEAST A STRATUM OF A LIQUID-PERMEABLE TRANSPARENT LAYER CONSTITUTING A RECEIVING LAYER FOR SAID COMPLEX AND SAID FILTER MEDIA AND ARRANGED IN SUPERPOSED RELATION TO SAID PHOTOSENSITIVE LAYER ON THE SIDE THEREOF WHICH INCLUDES SAID EXPOSURE FACE WHEREBY TO PROVIDE IN CONJUCTION WITH SAID PHOTOSENSITIVE LAYER A UNITARY STRUCTURE, HOLDING SAID LAYERS FIXED AGAINST ANY APPRECIABLE RELATIVE MOVEMENTS IN A DIRECTION PARALLEL TO THE PLANES OF SAID LAYERS WHILE TRANSPORTING TO SAID STRATUM SUFFICIENT SILVER COMPLEX TO FORM IN SAID STRATUM A POSITIVE SILVER IMAGE OF THE SAID LATENT IMAGE AND SUFFICIENT FILTER MEDIA TO FORM IN SAID STRATUM A COLOR SCREEN WHICH SUBSTANTIALLY DUPLICATES THE COLOR SCREEN THROUGH WHICH SAID PHOTOSENSITIVE LAYER IS ADAPTED TO BE EXPOSED, AND THEREAFTER SEPARATING SAID PHOTOSENSITIVE LAYER FROM SAID UNITARY STRUCTURE. 